kes If doing a mount, look for a slot, and if specified pass it to

     the SD so that it can load the autochanger.
kes  Return DVD=1 flag if a label command is done to a DVD. This
     permits setting VolParts to 1.
kes  Apply DVD patch from Richard Mortimer <richm@oldelvet.org.uk>, but
     rework ua_label code based on DVD media type to use DVD flag returned.